1. Field of the Invention
The present invention relates to a helical scan tape system, which is data storage with terabyte-class data storage capacity.
2. Description of the Related Art
A significant increase in the amount of information with developments of computers and the internet may require a data storage device having higher capacity and used for backing up the information. Examples of the data storage device include hard disk drives (HDDs) and storage tapes. To achieve such devices having higher capacities, surface recording density may be required to be increased. Examples of methods for increasing the surface recording density include a process of increasing track recording density by narrowing a recording wavelength; and a process of increasing the density in the track direction by narrowing a track pitch.
Read/write systems in tape streamers are divided into two: helical scanning employed in videocassette recorders, digital data storage (DDS), and advanced intelligent tapes (AIT); and linear scanning, in which digital signals are written and read by sliding a plurality of magnetic heads disposed in the transverse direction on a long magnetic tape in the longitudinal direction, employed in digital linear tape (DLT), linear tape-open (LTO), and the like.
To increase the recording density, Co-based magnetic tapes having a track recording density significantly higher than those of metal particle tapes (MP tapes) and produced by oblique evaporation have been increasingly used, thereby increasing not only the track recording density but also the storage capacity.
Among tapes used in the tape streamers, which are used for backups and archives, the magnetic tapes produced by oblique evaporation will be mainly used in the future because of high recording density. The magnetic layers of the magnetic tapes produced by oblique evaporation are formed by reactive vacuum deposition employing the oblique evaporation technique. The direction of inclined columns in the magnetic layer (easy magnetization direction) is not the in-plane direction but the oblique direction inclined relative to the in-plane direction. Thus, the high-output direction (forward direction) and the low-output direction (backward direction) are present depending on the traveling direction of the magnetic heads that record signals. In Japanese Unexamined Patent Application Publication No. 2003-59007, the magnetic tape produced by oblique evaporation is applied to the linear scanning read/write system. However, the magnetic tape produced by oblique evaporation is mainly applied to the helical scanning system, in which the traveling direction is a predetermined direction.